Corrugated sheet of fiber concrete and method of making it



FIBER CAT CORRUGATED SHE msmmn .A WILLIAMS.

CONCRETE AND METHOD OF MAKING IT.

ION HLED JUNE 9,1921- Patented. @015. 31, 1922.

en 1mm Patented 0a. 31, 1922.-

UNITED- STATES PATENT OFFICE.

SAMUEL A. WILLIAMS, 0]? LOCKPORT, NEW YORK.

CORRUGATED SHEET OF FIBER CONCRETE AND METHOD OF MAKING II'.

Application filed June a, 1921. Serial No. 476,204.

To all whom it may concern:

Be it known that I, SAMUEL A. WILLIAMS a subject of the King of Great Britain, and resident of Lockport, in the county of N iagara and State of New York, have invented new and useful Improvements in Corrugated Sheets of Fiber Concrete and the Method of Making Them, of which the following is a specification.

My invention relates to the manufacture of corrugated sheets of plastic and, preferably, refractory material for building and similar purposes, of which the material commercially known as corrugated transite is an example. Such material, made in rectangular corrugated sheets, is used in substantially the same manner as corrugated iron, but by reasons inherent in its structure and composition, has to be made considerably thicker than corrugated iron. The usual thickness of corrugated sheets of refractory building material is about one quarter of an inch; as sheets of this character are usually lapped one over the other when placed on a building frame, whether as siding or roofing, the undulating surface of one sheet should have the same contour as that of the sheet over which it laps, both for the sake of close fit and tightness to weather, and for secure fastening. As either side of one sheet may be lapped incontact with either side of another, it follows that on each sheet, the contour of each side should be a matrix ,.fo r,..the;other in other words curved linear elements, taken at 'rightangles to" the lines of corrugation, should be practically identical on both sides of a sheet. Such conformation has hitherto been obtained, and sheets so made are therefore thicker at the crowns of the corrugations than at the portions where the curve of corrugation reverses.

So far as I am informed, corrugated sheets of material of the general character specified have hitherto been made by passing green, i. e. freshly made, wet, and soft, sheets through corrugating rolls, and allowing the sheets thus corrugated to set while resting on suitably corrugated forms which support the corrugations and prevent them from being deformed by sagging, until the cementitious material in the sheets has become permanently set. The flat sheets which have thus been mechanically shaped have been either laminated sheets of asbestos fiber paper saturated with water containing a hydraulic cement in suspension, or pressed non-laminated sheets, such as the asbestos wood, commercially so-called. In either case, or with eitherstarting material, the fiexion of the green sheet under the action of corrugating rolls disturbs the structural relation between fibers and cementitious material, especially at the crowns of the corrugations, where the tendency'of fibers to draw apart at the outer'portions of each curve is manifested by subse uent weakness of the sheet atthese crowns, i not by visible cracks in the material. Moreover, as the two surfaces ofsuch a sheet must be as nearly as possible identical, in contour, the regions midway between successive maxima of the repeated curve must be pressed thinner than the material at the maxima; and while the material is green and to some extent plastic, it cannot flow in response to the action of the rolls without interior dislocations of the structure originally formed as a substantially fiat felted or compacted sheet.

The object of my invention is to produce a corrugated sheet of fiber concrete material, possessing the requisite identity in curvature at the two sides, non-laminated, homogeneous in density, and of uniform internal structure throughout.

The terms in which this object is stated eliminate the laminated or paper-board type of material. In order to produce a corrugated sheet having the above named characteristics, the material must be made to assume an"apprf oximation to its final form while still freely fluid, in order that pressure exerted on it shall be uniform at all points. I accomplish the desired results by press-molding the corrugated sheet initially into the undulated form, in a filter press provided with a filter bed and press-head having the desired complementary undulated surfaces. The operation of this press involves a new method of mani ulatin the fiber-concrete material, and t 0 pro uct is itself a novelty, though superficially resembling the corrugated fiber-concrete sheets which have been on the market for a considerable time. The apparatus process or method, and product are all described herein, the method and product are herein claimed, while the apparatus is the sub'ect of claim in an application for Unite States Letters Patent, filed by me concurrently herewith, serially numbered 476,205.

In the drawings hereto annexed, whichillustrate my invention,

' filter bed by and. completely fills the space between the.

.. forated or reticulated the usual t pe of hydraulic press.

into contact with the Figure 1 is a view in vertical section of parts of a press, including the mold box, filter bed, and press-head, the ress-head about'to descend-upon a mass of uid fiberconcrete material.

' of much greater extent than here indicated.

The press itself, comprising all the accessories to the operation of the press-head, box,

and filter bed, is not shown, as this will be of by D, D; the B, the press-head by H. The surface 1 of the bed and 2 of the press-head are undulated or corrugated, andare complementary, so that if the head were brought bed, the two surfaces would fit each other. The fiber-concrete ma- The mol -box is represented terial is represented in Fi s. -l and 2 by M, the finished product in' ig. 3 by C, C. The materialM, whichmay be any suit- [able Wet fiber-concrete mixture, as for in-- stance one comprising short asbestos fibers or ground serpentine, magnesia, is a wet fluid; mud, containing a great excess of water over the quantity required for setting the cementitious material, and therefore flows readily and promptly in response to the displacements occasioned by the intrusion ofthe salient ridges of the press-head. Thus,when the ress-headfirst acts upon the material M, t e latter flows press-head and filter bed. The initial pressure, which begins to force the excess of water in the material through the percovering of the filter bed, is communicated to all parts of the material and at any point therein is exerted equally in all directions, in obedience to the laws of behavior of liquids. so, that-is: The solid materials, fiber and cement, which with the water form a thin mud, produce. a. condition analogous to viscosity, but nevertheless the mud is sufficiently fluid before pressure-filtration, to

produce the distributions and equalization .of pressure substantially as if the mud were a homogeneous liquid.

the fluid mobility flow diminish.

As the press-members approach each other as the requirements of r the situation maybe do- That as the-viscosity of the but progressive scribed thus material increases, the necessity and-op} 'more fluid stages.

and water,

Practically close. interfittin of the material diminishes,

portunity for flow from regions of higher to those of lower pressure diminish. The relative difference in thickness of the mass at the crown-portions of the corrugations and at the portions intermediate between the crown-portions, respectively, is established while the material is in its initial and As the fiuidityof the material diminishes, so that, by reason of the curved outlines of the press-head and filter bed the pressure normal to the surfaces of the material varies from a maximum at the crowns to a minimum atthe regions of curvature reversal, the quantity of water remaining to be expressed from the solids becomes, by reason of variation in thick-' ness of the material, proportionally less per unit of volume at the thinner parts than at the thicker so that the pressures at the thinner portions are adequate to express water thence as completely as the'higher normally exerted pressures at the thicker crowns; Thus, despite the curved conformation of the finally compressed sheet, its structure is uniformly dense throughout, and the intrinsic strength of the material, after setting},l is conserved.

e relative values of the normally exerted pressures on the material at the final .instant of compression, are indicated by the dimension lines a and b, a; and b5. in Fig.

2; these lines likewise indicate the thickness of the sheet. C shown in Fig, 3.

On removal from the press, the fiber-concrete corrugated sheets are laid, one upon another, the bottom sheet resting on a corrugated bed plate, which fits the corrugations of the sheet and supports it while setting.

Fiber-concrete sheets, made in the manner above described, are much stronger and resistant to any stress, than corrugated sheets made as heretofore. by roll-corrugating sheets of the same kind, ori 'nally presse in the flat, and stronger st 1 in comparison with lamented, roll-corrugated sheets, made of material of similar character and constituents. The corrugated surfaces of these new sheets are, moreover, more true to form than those of roll-corrugated sheets;

therefore the improved corrugated sheets fit more exactly together when lapped, and are more effectively weather-tight. I The of thin corrugated surfaces is illustrated in Fig. 3.

The above described method is subject to no practical limitation in respect to the thickness of the corrugated sheet to be manufactured. Corrugated sheets of any desired thickness can be thus produced, and

will, through the. operation of the method,

be uniform in density and structure and, in particular, homogeneous in regard to the distribution and binding relat onship of fibers incorporated in the sheets. By whatsoever process manufactured, fiat sheets of the general character described cannot practically be corrugated unless thin enough to conform to the corrugating rolls or other instruments without undue rupture at the convexities. In no case can flat sheets be corrugated without being subjected to such internal and local strains as disturb their original homogeneity and strength.

density and fiber-distribution the material to flow in-the contracting space with increasing viscosity asthe compression progresses, and producing uniform and internal structure in the finally compacted material.

2. Unitary, non-laminated, fiber-concrete sheet, corrugated, uniform as densig and fiber-distribution.

3. nitary, non-laminated, fiber-concrete corrugated,

regards sheet, uniform as two undensity regards 30.

dulating surfaces of said sheet being substantially identical in contour, so that either surface of such sheet will fit either surface.

of a similar sheet.

Signed by me at Boston,Massachusetts, this fourth day of June, 1921.

SAMUEL. A. WILLIAMS. 

